9 Accessibility principles and tools

Accessibility is about making websites useful for everyone, regardless of ability or disability.

One way to determine if websites are accessible is to compare them to a set of standards, such as the  Web Content Accessibility Guidelines (WCAG) by the World Wide Web Consortium.

WCAG principles and guidelines

WCAG is framed around 4 principles: perceivable, operable, understandable and robust.

Perceivable means that the website’s interface and content are presented in a way that users can comprehend, including people using assistive technologies.

Operable means that people must be able to use your website.

Understandable means that people can understand the content on your website.

Robust means that your website must be able to work with different technologies.

Under the 4 principles, there are 13 guidelines. These are basic goals that authors should strive to achieve to make content more accessible for users with disabilities (WCAG, 2023).

How to apply the WCAG standards in textbook projects

The following suggestions can help improve the accessibility of your textbook.

Perceivable

• Provide non-text content with a text alternative, e.g., alt text for informative images.
• Provide a text transcript for audio recordings. This may include speech as well as other sounds that are important for understanding the content.
• Provide a text description for video recordings. This can include descriptions of actions, facial expressions, non-speech sounds and spoken dialogue.
• Use information such as text, in addition to colour, to convey meaning.
• Use sufficient colour contrast between the text and its background to make the content easy to see. Normal text should have a ratio of 4.5:1, and large text should have a ratio of 3:1.

Operable

• Check that all parts of the book can be accessed using a keyboard only.
• Check that the entire book can be accessed with devices other than a keyboard (e.g. mouse, touchscreen, speech-to-text).
• Do not skip heading levels (e.g. h2 followed by h4.).
• Make sure that people have enough time to read and use your content (e.g. being able to pause and start a video).
• Check that animated content doesn’t flash more than 3 times per second (so sensitive users do not have seizures or physical reactions).
• Provide meaningful text for all links to help users predict where they are going. Avoid using links such as ‘click here’ or ‘read more’.
• Open links in the same window or tab whenever possible.

Understandable

• Use simple language so that the content is easy to understand. Define jargon or technical terms in the text. You can check readability if you are using Microsoft Word. Alternatively, you can use an app such as Hemingway.
• Web pages should be structured to ensure they are predictable in appearance and operation for users (e.g. consistent navigation and page features).

Robust

• Write web pages in HTML that is compatible with current and future assistive technologies.

Accessibility checking tools

Many free and paid tools are available to perform accessibility checks on your content. These include:

• WAVE accessibility evaluation tool is a browser extension that reports accessibility errors in web pages.
• NVDA screen reader is free to experience screen reading of your content.
• WebAIM contrast checker measures the contrast ratio of foreground to background colours.
• The Hemingway App provides a readability score of text and highlights sentences that are hard to read. Remember to check their data usage policy before you use it.
• Adobe Acrobat Pro includes an accessibility checker for PDF files.
• Ace by DAISY checks the accessibility of EPUB files.

Pressbooks and accessibility

Publishing tools, such as Pressbooks, which conform to the WCAG make it easy to create accessible content. Pressbooks also releases Voluntary Product Accessibility Template reports, or VPATs, for the reading interface and authoring platform, which report on conformance for each WCAG success criterion.  Conformance reports are useful tools for pinpointing areas where additional action is needed to meet the WCAG. For example, in Pressbooks, HTML table header tags (<th>) must be manually inserted by users to make content accessible.

If you use a publishing tool other than Pressbooks,  additional steps may be taken to comply with the WCAG. Look for the tool’s accessibility statement and, ideally, if they have published an accessibility conformance report.

Accessibility statements

Accessibility statements are included in the front or back matter of open textbooks. Their main purpose is to communicate known accessibility issues to readers.  Accessibility statements are also used to provide:

• information about an organisation’s commitment to accessibility
• information about what an organisation is doing to make a resource accessible and the accessibility guidelines that are being followed
• contact details for users to get help.

Below is an example of Monash University Library’s accessibility statement that you can adapt to suit your textbook.

Accessibility information

We believe that education must be available to everyone, which means supporting the creation of free, open, and accessible educational resources. We are actively committed to increasing the accessibility and usability of the textbooks we produce.

This resource was created in line with the WCAG guidelines and aims to meet the criteria listed on our Accessibility Checklist [PDF, 21 KB].

If you have issues accessing this resource please fill in the Monash Open Textbook Problem Feedback form.

References

World Wide Web Consortium (WCAG) (2023).  WCAG 2 Layers of guidance. https://www.w3.org/TR/WCAG21/#wcag-2-layers-of-guidance